The Research Of Variable Diameter Pipe Hot Extrusion Forming Technology

At present，Aluminum alloy variable diameter pipe mainly adopt the method ofcasting and welding for the production in the civilian market.But in the military andaerospace market, due to the use of performance requirements for parts is higher, mainaluminum alloy variable diameter pipe is the adoption of high performance materials formachining or forging forming method for production. In view of the technical bottlenecksof the low utilization rate of raw materials, poor dimensional accuracy and low finishedproduct performance, production cycle is long, can’t batch production with high qualityexist in above production methods. Based on the existing deformation of2A12aluminumalloy material performance and on the basis of studying the forming process, through thecomputer finite element simulation method,make the hot extrusion forming technology of2A12aluminum alloy variable diameter tubewhich can solve the problems in existing production process.First, according to the need of the computer finite element simulation method,geometric model of three-dimensional modeling tools UG established mold, thentransformed it into rigid-plastic finite element model of the simulation,analysis of the keyparameters involved in the simulation process, to establish a basis for simulated formingprocess.Through the three-dimensional numerical simulation of the hot extrusion process ofvariable diameter tube, to analysis flow law of the metal of forming process, comparedifferent forming process, as well as the analysis of different deformation temperature,deformation velocity and friction condition on the forming process, to determine the hotextrusion forming of2A12aluminum alloy variable diameter tube using φ82×25mm blank,extrusion temperature is460℃, deformation rate of5mm/s, using oil-base graphitelubricant.In the based on the analysis of the simulation results, prepare the hot extrusionforming technology of2A12aluminum alloy variable diameter tube, design reasonablestructure of the forming mould, then carries on the production manufacture processparameters to validation the preparation process, formulation and design of die structure.Through the inspection the product of trial production’s dimensions and performance canmeet the design requirements, which specifies that the design of die structure andtechnological parameters are reasonable, and can achieve expected purpose, it has a certainreference function in the forming process of such parts of variable diameter tube.